// 内存管理服务实现

use std::sync::Arc;
use log::info;
use crate::core::{Service, ServiceStatus};
use safe_ffi::core::types::MemoryPermissions;

/// 内存管理服务
pub struct MemoryService {
    status: ServiceStatus,
}

impl MemoryService {
    pub fn new(_capability: Arc<()>) -> Result<Self, String> {
        Ok(MemoryService {
            status: ServiceStatus::Stopped,
        })
    }

    /// 分配内存
    pub fn allocate_memory(&self, size: usize) -> Result<Vec<u8>, String> {
        info!("Allocated {} bytes of memory", size);
        Ok(vec![0u8; size])
    }

    /// 释放内存
    pub fn free_memory(&self, _buffer: Vec<u8>) -> Result<(), String> {
        info!("Freed memory buffer");
        Ok(())
    }

    /// 获取内存统计信息
    pub fn get_memory_stats(&self) -> Result<MemoryStats, String> {
        // 这里实现获取内存统计信息的逻辑
        Ok(MemoryStats::default())
    }
}

impl Service for MemoryService {
    fn name(&self) -> &'static str {
        "memory"
    }

    fn start(&mut self) -> Result<(), String> {
        info!("Starting Memory Service");
        self.status = ServiceStatus::Starting;
        
        // 这里可以添加内存服务启动逻辑
        // 例如：初始化内存池、设置内存保护等
        
        self.status = ServiceStatus::Running;
        info!("Memory Service started successfully");
        Ok(())
    }

    fn stop(&mut self) -> Result<(), String> {
        info!("Stopping Memory Service");
        self.status = ServiceStatus::Stopping;
        
        // 这里可以添加内存服务停止逻辑
        // 例如：释放所有分配的内存、清理资源等
        
        self.status = ServiceStatus::Stopped;
        info!("Memory Service stopped successfully");
        Ok(())
    }

    fn status(&self) -> ServiceStatus {
        self.status.clone()
    }
}

/// 内存统计信息
#[derive(Debug, Clone)]
pub struct MemoryStats {
    pub total_memory: u64,
    pub used_memory: u64,
    pub free_memory: u64,
    pub allocation_count: u64,
    pub deallocation_count: u64,
}

impl Default for MemoryStats {
    fn default() -> Self {
        MemoryStats {
            total_memory: 0,
            used_memory: 0,
            free_memory: 0,
            allocation_count: 0,
            deallocation_count: 0,
        }
    }
}

/// 内存区域信息
#[derive(Debug, Clone)]
pub struct MemoryRegion {
    pub start_address: u64,
    pub size: usize,
    pub permissions: safe_ffi::core::types::MemoryPermissions,
    pub is_allocated: bool,
}

/// 内存池管理
pub struct MemoryPool {
    regions: Vec<MemoryRegion>,
    total_size: usize,
    used_size: usize,
}

impl MemoryPool {
    pub fn new(total_size: usize) -> Self {
        MemoryPool {
            regions: Vec::new(),
            total_size,
            used_size: 0,
        }
    }

    pub fn allocate(&mut self, size: usize) -> Option<MemoryRegion> {
        if self.used_size + size > self.total_size {
            return None;
        }

        let region = MemoryRegion {
            start_address: 0, // 实际实现中需要计算地址
            size,
            permissions: MemoryPermissions::read_write(),
            is_allocated: true,
        };

        self.regions.push(region.clone());
        self.used_size += size;
        Some(region)
    }

    pub fn deallocate(&mut self, start_address: u64) -> bool {
        if let Some(index) = self.regions.iter().position(|r| r.start_address == start_address) {
            let region = self.regions.remove(index);
            self.used_size -= region.size;
            true
        } else {
            false
        }
    }
}